Chironex fleckeri

IDENTIFICATION

FAMILY NAME

Chirodropidae

GENUS NAME

Chironex

SPECIES NAME

Chironex fleckeri

COMMON NAME(S)

Australian box jellyfish

Box jellies

Box jelly

Box jellyfish

Chironex box jellyfish

Indringa

Sea stinger

Sea wasp

HABITAT

Distribution

These tropical jellyfish are mainly found in coastal waters in tropical areas of northern Australia. These animals frequent the shore area adjacent to mangrove creeks in which they breed, and from which they swim to feed in summer (October to May). The closer the geographical location to the equator, the greater the number of months Chironex fleckeri is found. In Darwin, Chironex fleckeri stings have occurred for every month of the year, except for one month. When fishing for prey they favor calm water close to shore, free of snags over clear sandy bottoms, where they extend and trail their curtain of tentacles behind them.[1]

INTERVENTION CRITERIA

Intervention Level

Child and Adult

Medical observation, preferably in an advanced care facility with Box Jellyfish Antivenom available is recommended for:

- Any individual stung or suspected to have been stung by a box jellyfish

Observation Period

Observation at Home

All patients require medical attention.

Medical Observation

Asymptomatic patients should be observed for 2 hours. If they remain asymptomatic in this time frame, the patient may be discharged into the care of a reliable observer and given instructions to return should any symptoms develop.

Stings may result in severe envenoming; symptomatic patients must not therefore be discharged until their symptoms have subsided.

Investigations

Sticky tape or scalpel sampling can be performed to identify the jellyfish in question, sticky tape is applied to skin or the skin is scraped with a scalpel and then transferred to a microscope slide for examination; this allows nematocysts to be identified on the basis of morphology.[2][3]However this currently is a research tool only. A negative result does not rule out a jellyfish sting.

Admission Criteria

Any patient with symptoms must be admitted to a medical facility with Box Jellyfish Antivenom and advanced life support.

TREATMENT

TREATMENT SUMMARY

Most stings are minor but all must be treated as potentially lethal.

In all cases retrieve and restrain the victim on the beach, prevent rubbing of attached tentacles and vigorous muscular activity. Commence and sustain cardiopulmonary resuscitation (CPR) if indicated, this always takes absolute priority.

Flush the affected area liberally with vinegar for at least 30 seconds, and only then carefully remove any adherent tentacles.[4] If the effects are minor, pain may be managed with local application of ice,[5][6] simple analgesia, and oral antihistamines; there should be early medical inspection in case of local skin damage. If pain does not respond, parenteral opioid analgesia may be required, or administration of Box Jellyfish Antivenom which appears effective for pain relief if administered early. Antivenom is also indicated in severe envenomings to reduce life-threatening complications, and possibly reduce scarring.[7]

Cardiac dysrhythmia and arrest are particular concerns, and possibly may develop within minutes of the stinging contact. Pulmonary edema and respiratory depression/failure may subsequently evolve. Multiple vials of antivenom should be administered for these indications, but its efficacy in the management of cardiorespiratory dysfunction remains uncertain,[7] and advanced supportive care, including mechanical ventilation, is likely required to maintain such patients.

Dermonecrosis is a frequent complication of serious stings, and box jellyfish antivenom has been reported to improve both acute and long-term cutaneous damage.[8] Acute skin markings often resolve spontaneously. Thus acute dermonecrosis should be treated as a burn with specific attention to avoiding secondary bacterial infection. Delayed hypersensitivity reactions are a common late complication of stings occurring some 7 to 14 days after the event.[9] Serum sickness is a potential concern in those receiving antivenom, particularly multiple doses.

EMERGENCY STABILIZATION

Ensure Adequate Cardiopulmonary Function

Airway

Ensure the airway is protected if compromised (intubation may be necessary).

Immediately establish secure intravenous access.

Cardiac Arrest

Cardiac dysrhythmia or arrest may occur within minutes of a sting – particularly in children. Commence and sustain cardiopulmonary resuscitation (CPR) if indicated, this takes priority over application of vinegar to neutralize tentacle stinging apparatus.

Prolonged cardiac resuscitation following standard ACLS protocols is warranted as recovery with a good neurological outcome is reported in poisoned patients receiving CPR for periods of 3 to 5 hours.[10]

Cardiopulmonary resuscitation should therefore be prolonged, and ideally not abandoned until at least 6 vials of intravenous box jellyfish antivenom have been administered.[11]

Hypotension

CHILD

Where the systolic blood pressure is below normal blood pressure ranges for the age group:[12]

Age (years)

Normal Systolic Blood Pressure (mm Hg)

< 1

70 to 90

1 to 2

80 to 95

2 to 5

80 to 100

5 to 12

90 to 110

> 12

100 to 120

Administer normal (0.9%) saline

10 mL/kg IV over 5 to 10 minutes

If the systolic blood pressure does not return to the normal range, give a further 10 mL/kg body weight normal saline over 5 to 10 minutes. If intravenous access cannot be obtained consider intra-osseus access.

ADULT

Administer a bolus of normal saline if systolic blood pressure is less than 100 mmHg.

Normal (0.9%) saline dose:

10 mL/kg IV over 5 to 10 minutes

If the systolic blood pressure does not return to the normal range, give a further 10 mL/kg body weight normal saline over 5 to 10 minutes.

Flush with Vinegar

Retrieve and restrain the victim on the beach and prevent tentacle rubbing and vigorous muscular activity. Immediately douse the sting area liberally with vinegar for a minimum of 30 seconds;[13] do not attempt to remove adherent tentacles before this step, unless no vinegar is available, in which case carefully pick off the tentacles.

Pressure Immobilization First Aid

Pressure immobilization first aid was proposed to be beneficial because of its effectiveness in treating elapid snake and funnel web spider bites,[14][15] however there is no evidence to support the use of pressure immobilization bandages in the management of jellyfish stings.[16][17] Evidence suggests it may actually increase the amount of venom that is injected into the victim.[18] The Australian resuscitation council has announced a change in advice to a more neutral position.[19]

Emergency Monitoring

If there are signs of systemic envenoming:

Heart rate/rhythm

Pulmonary function

Level of consciousness

DECONTAMINATION

Skin

Flush the affected area with vinegar (3 to 10 % acetic acid in water) as soon as possible,[20][21] and continue to irrigate for 30 seconds. After flushing, carefully remove any adherent tentacles.[4]

Vinegar may irritate the sting sites, but should still be applied.[22] It is not designed to relieve pain associated with jellyfish stings, but to prevent further discharge of nematocysts. Nematocyst inhibition and analgesia are two distinct and separate areas of management.

The fresh sting area should never be rubbed with sand, towels or anything else. Methylated spirits is not recommended.[4]

Eye

Remove contact lenses. Irrigate immediately with water or saline for at least 30 minutes. If the eye is contaminated with solid particles, the eyelid should be completely everted and any solid material removed as quickly as possible whilst continuing to irrigate. A topical anesthetic may be necessary in some patients to enable the patient to open their eyelids sufficiently for effective irrigation.

The eye should be examined immediately following flushing with a slit-lamp microscope and fluorescein stain. All patients should be reviewed the following day. Any evidence of injury requires specialist ophthalmological assessment.

ANTIVENOM

Box Jellyfish Antivenom

There have been conflicting studies over the efficacy of box jellyfish antivenom, its efficacy remains to be proven, particularly in relation to preventing fatalities. This is because of the dramatic nature of the sting, with death or survival usually determined within minutes.[11] Studies in animals have shown that the antivenom is largely ineffective in preventing cardiovascular collapse even when administered before envenoming;[23] this lack of effect may be due to the antivenom being unable to bind venom in sufficient time to prevent the venoms rapid effects.[23][24]

Whether the antivenom has the potential to reverse life-threatening cardiotoxicity in humans remains uncertain; the antivenom would need to be given early and in large doses (up to 6 vials) in such a scenario.[25][11] Should more than 6 vials be required contact an experienced medical toxicologist for advice. The antivenom may be beneficial if given early in the relief of severe skin pain.[8][26]

Indications

Box Jellyfish Antivenom should be administered to any patient if:

- Cardiorespiratory dysfunction/arrest is apparent

- Severe pain is unresponsive to other managements

Other suggested, but not uniformly accepted, indications include:

- The total sting area is greater than the area equivalent to one half of one limb (especially in children)

- Cosmetic damage such as to the face is likely (the possible benefit must be carefully considered given the risks of antivenom administration)

However, these indications should be discussed with a medical toxicologist.

Dose and Administration

Only administer if clearly indicated. Note the dose for a child is the same as that for an adult, and that while IV administration is preferred, the IM route is considered safe and may be considered in the field situation. However, the IM route, theoretically, may not be as effective.

Pre-medication is not recommended although controversy exists.[27][28][29]

Prior to use of jellyfish antivenom, ensure adequate resuscitation equipment is available for the management of anaphylaxis, and that an appropriate dose of epinephrine (adrenaline) is drawn up as outlined in management of anaphylaxis. Note that anaphylaxis has not yet occurred with this antivenom and the need for early administration in severe cases may outweigh the need to be fully prepared to treat anaphylaxis.

Preferably dilute antivenom up to 1 in 10 in an isotonic solution (e.g. normal [0.9%] saline); dilution should be less for children due to fluid load. Administer intravenously via a drip-set, commence very slowly and increase rate if there is no adverse reaction. Total dose should be given over 15 to 30 minutes.

Patients must be closely monitored for anaphylaxis during and for 30 minutes after the infusion.

Further Box Jellyfish Antivenom doses

Should cardiovascular compromise not be reversed with the initial dose, administer a further dose (up to 3 vials) IV.[30]

Contra-indications

There is no absolute contra-indication to this potentially life-saving intervention.

Those at increased risk of severe reaction include patients with history of:

Previous reaction to antiserum

Asthma

Atopy

Adverse Effects

Anaphylaxis

The antivenom being a foreign protein could cause sensitization and, therefore, should not be given for insignificant lesions or wheals.[15]

Serum Sickness

Serum sickness may occur some 4 to 14 days following antivenom administration.

Patients should be observed for, and made aware of, the signs and symptoms of serum sickness including:

Rash

Fever

Joint aches

Pains

Malaise

Serum sickness may be managed with antipyretics and analgesics, as well as anti-inflammatory agents including antihistamines and corticosteroids:

Prednisone dose

ADULT

60 mg daily for 7 to 14 days with tapering

Severe cases may require hospitalization.

SIGNS AND SYMPTOMS

The Box jellyfish is one of the most dangerous venomous creatures in the world, however, most typical stings rarely require hospitalization.[11][9][6]

Following exposure, the victim may experience immediate excruciating pain which increases in mounting waves, despite removal of the tentacle. The victim may scream and become irrational.[31][32] Areas of contact appear as purple or brown lines often compared to the marks made by a whip.[31] A pattern of transverse bars is usually visible and whealing is prompt and massive. Edema, erythema, and vesiculation soon follow and when these subside patches of full thickness necrosis are revealed.[31]

Patients may develop a variety of systemic effects that include acute pulmonary edema, cardiovascular instability and dysrhythmias, hypertension, hypotension, shock, and cardiac arrest. When death occurs it is usually due to a (presumed) cardiac arrest on the beach.

Routes of Exposure

Clinical effects may develop following contact with intact or dismembered jellyfish, or nets containing body parts. Exposures generally occur when people are swimming in the sea or when specimens are washed up on the beach and handled or stood on. Jellyfish do not “attack” humans and stings are usually the result of a creature drifting into humans or humans colliding into a jellyfish.

Onset/Duration of Symptoms

Local effects are generally noted immediately. Victims experience intense excruciating localized skin pain, peaking at 15 minutes and waning over the subsequent 24 hours; edema, erythema and vesiculation occur initially and when these subside (after some 10 days) patches of full thickness necrosis are revealed. Death, if it occurs, is usually within 20 minutes of the sting.[11]

Severity of Envenoming

Severity is dependent upon area of discharging tentacle contact. Involvement of greater than 10% skin area is potentially lethal, especially in children.[7] Death follows cardiopulmonary failure.

Mild Box Jellyfish Envenoming

Moderate Box Jellyfish Envenoming

Severe Box Jellyfish Envenoming

Local pain

Cutaneous linear marks of sting

Severe local or generalized pain

Nausea

Vomiting

Tachycardia

Acute respiratory distress

Dysrhythmias

Shock

Acute pulmonary edema

Respiratory failure

Cardiac arrest

Death

CHRONIC EFFECTS

Delayed hypersensitivity reactions may occur in patients following stings. The reaction consists of a pruritic erythematous maculopapular rash that appears at the initial tentacle contact points and occurs 7 to 14 days after envenoming. The reaction may spontaneously resolve; most recover following treatment with oral antihistamines and topical corticosteroids.[9]

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The University of Otago, the New Zealand National Poisons Centre and Intergen will not be responsible for damages of any nature resulting from use or reliance upon this information.